[webkit-dev] Position on emerging standard: video.requestAnimationFrame()

[Thomas Guilbert]

The idea was to reuse an API name that developers are already
familiar with, in a similar context. The name is also being used in
XRSession (
https://developer.mozilla.org/en-US/docs/Web/API/XRSession/requestAnimationFrame),
and in OffscreenCanvas (or technically DedicatedWorkerGlobalScope).
The AnimationFrameProvider
mixin
<https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#animationframeprovider>
could
also be updated so HTMLVideoElement can extend it.

Yes, this isn't formally spec'ed out, but it will be. For now, they are
added to the task queue and run like any other task. So, going off the spec
you linked, I think this would be "5) Perform oldestTask's step"  and not
"10) Rendering: [...] 11. Foreach document run animation frame callbacks
for that Document".

On Tue, Jan 21, 2020 at 1:01 PM Simon Fraser <simon.fraser at apple.com> wrote:

> On Jan 21, 2020, at 12:37 PM, Thomas Guilbert <tguilbert at google.com>
> wrote:
>
> Hello,
>
> I'm reaching out to see if webkit would like to weigh in on the following proposal:https://discourse.wicg.io/t/proposal-video-requestanimationframe/3691
>
> The HTMLVideoElement.requestAnimationFrame() API allows web developers to be notified when a video frame has been presented for composition, and provides metadata for that frame.
>
> If you want to try it out, a prototype is available in Chromium Dev,
> behind the enable-experimental-web-platform-features flag.
>
>
> This is not official feedback, but I have some issues with the proposal.
>
> First, the name is confusing. It sounds like you're requesting a frame
> from the video, but it's really a "frame available" callback. Why not call
> it onFrameAvailable()?
>
> Second, its interaction with normal requestAnimationFrame() and the HTML
> event loop needs to be better defined. Where in in the
> https://html.spec.whatwg.org/multipage/webappapis.html#event-loop-processing-model do
> these callbacks fire?
>
> Simon
>
>
>
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